Near-Field Localization with Limited RF Chains: An Array Partitioning Approach

Equipping each antenna with an independent radio frequency (RF) chain in extremely large-scale antenna arrays (ELAA) requires unaffordable hardware and power consumptions. Analog beamforming is a common technology to reduce the number of RF chains. However, existing near-field positioning algorithms cannot adapt to analog beamforming, resulting in the algorithm being unusable when the RF chains are limited. This paper addresses the near-field localization problem for a base station (BS) with an ELAA and limited RF chains. Following the array partitioning approach, we divide the subarrays into groups and use a linear function to approximate the angles of arrival (AoA) variation within each group. We propose a message-passing algorithm, called array-partitioning-based location estimation with AoAs block-wise linearization (APLE-ABL), to estimate the user position. The simulation results show the effectiveness of our algorithm.